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4 marksComputer Architecture

CAPE Computer Science Unit 1 · 2015 · Paper 2 · Question 1(a)(ii)

Design of a security alarm system that sounds when the switch is enabled and a window or door is opened.

Using only primary logic gates, design and draw the circuit for the alarm system.

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Other parts of this question

  1. 1(a)(i)Write down the truth table showing all possible input bit combinations and outputs for the alarm scenario.[8 marks]
  2. 1(b)Explain the meaning of the term 'demultiplexer'.[2 marks]
  3. 1(c)Draw a clearly labelled block diagram of a 3-to-8 line decoder.[3 marks]
  4. 1(d)Determine the decimal equivalent of the hexadecimal number 1A53, showing all working.[3 marks]
  5. 1(e)Find the 8-bit two's complement of -21, showing all working.[2 marks]
  6. 1(f)Given a floating-point format of 1-bit sign, 3-bit exponent, and 5-bit mantissa, calculate the decimal representation of 001101011, showing all working.[3 marks]

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